This invention relates generally to skin-piercing devices and methods, and in particular, to reusable skin-piercing devices and methods, where the reusable skin piecing device is heat-sterilized prior to reuse.
Diabetic people use lancets to pierce their skin in order to obtain small samples of blood for electrochemical, photonic or other glucose assays. The lancets commonly used are made of steel. Even though it is recommended that they be used only once, while the lancets are still sterile, many diabetic people use them multiple times to lower the cost of monitoring their glycemia (by measuring blood glucose concentration).
There are several problems with using the lancet more than once. For example, after its first use the lancet device is no longer sterile. Also, when used more than once, the point of the lancet is blunted. After a few piercings with the lancet, the lancet no longer punctures the skin. Therefore, the skin area impacted by the tip of the lancet increases, and the force driving the lancet through the skin must be increased. With the increase of force and of the pierced area, the pain associated with obtaining the sample becomes greater. In addition, the spatial definition, i.e., the accuracy of the placement in the pierced zone of the skin relative to an object that is part of the glucose assaying system, degrades when the tip is blunted.
In accordance with the present invention, the above and other problems are solved by providing a reusable ceramic skin-piercing device and method. The skin-piercing device is capable of piercing the skin so as to make a sample of biological fluid available for an assay, and includes a skin-piercing element which is heated prior to use to a sufficiently high temperature to deactivate or kill pathogenic microorganisms. The device is heat-sterilized, being heated by passing an electrical current through a resistive region in thermal contact with the heat-conducting ceramic skin-piercing device. The device is used to obtain a small, usually less than 5 xcexcL, sample of blood or of subcutaneous fluid for an assay, particularly of glucose.
Another embodiment of the invention is a skin-piercing device having a skin-piercing element that includes a blade (e.g., a ceramic blade) and a sleeve disposed around the skin-piercing element. The sleeve includes an elastomeric material and a sterilizing agent. The sterilizing agent sterilizes the skin-piercing element after use.
The skin-piercing element is made of a hard refractory ceramic material. In another embodiment, the ceramic material may be a composite, for example, a composite of a ceramic material and a metal, or of multiple ceramic materials.